Proinflammatory cytokines inhibit osteogenic differentiation from stem cells: implications for bone repair during inflammation

SummaryObjectiveThe effects of inflammation on bone development from mesenchymal stem cells (MSC) are unclear due to the difficulty in isolating MSC. The aim of this study was to develop a MSC isolation method and to determine the in vitro effects of interleukin-1β (IL-1β) and tumor necrosis factor α (TNFα) on their osteogenic differentiation.MethodsMurine MSC were isolated from the limbs of C57/Bl6 mice through collagenase digestion of bone and enriched as the Stem cell antigen (Sca-1)+ CD31− CD45− population, using lineage immunodepletion, followed by fluorescence-activated cell sorting (FACS). They were differentiated along the osteoblast linage in the presence or absence of IL-1β and TNFα. Mineralization was measured as was the expression of a number of osteogenic genes by quantitative polymerase chain reaction (PCR).ResultsWe show that osteogenic differentiation from the MSC population is suppressed by IL-1β and TNFα. In addition to suppression of bone mineralization, both cytokines inhibited the differentiation-associated increases in alkaline phosphatase (ALP) activity and the gene expression for ALP, α1(I) procollagen, runt-related transcription factor 2 (Runx2) and osterix. However, only TNFα inhibited osteonectin and osteopontin mRNA expression and only IL-1β reduced cell proliferation.ConclusionsThe convenient isolation technique enables the easy generation of sufficient MSC to permit the molecular analysis of their differentiation. We were thus able to show that the proinflammatory cytokines, IL-1β and TNFα, can compromise bone development from this primary MSC population, although with some significant differences. The potential involvement of specific inflammatory mediators needs to be taken into account if optimal bone repair and presumably that of other tissues are to be achieved with MSC

Tomonaga-Luttinger features in the resonant Raman spectra of quantum wires

The differential cross section for resonant Raman scattering from the collective modes in a one dimensional system of interacting electrons is calculated non-perturbatively using the bosonization method. The results indicate that resonant Raman spectroscopy is a powerful tool for studying Tomonaga-Luttinger liquid behaviour in quasi-one dimensional electron systems.Comment: 4 pages, no figur

Application of a conventional fishery model for assessment of entrainment and impingement impact

A conventional stock assessment model is applied to determine the impact of entrainment and impingement at the Monroe Power Plant on the yellow perch stock of the Western basin of Lake Erie. Parameters of the model are estimated using power plant data, biological data available in the literature, and commercial catch data. The model is applied to estimate the age structure and biomass of the perch stock and to estimate the impact of the power plant on abundance of the impingeable stock and abundance and biomass of the exploited stock. The level of impact was examined under a range of mortality conditions. Under the most extreme conditions examined of full pumping, high fishing mortality, and low natural mortality, the fishable biomass is reduced by 1.7%. This impact is not large, but there are several other power plants and many additional water intakes around the Western basin of Lake Erie.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42645/1/10641_2004_Article_BF00001790.pd

Mutual Events in the Cold Classical Transneptunian Binary System Sila and Nunam

Hubble Space Telescope observations between 2001 and 2010 resolved the binary components of the Cold Classical transneptunian object (79360) Sila-Nunam (provisionally designated 1997 CS29). From these observations we have determined the circular, retrograde mutual orbit of Nunam relative to Sila with a period of 12.50995 \pm 0.00036 days and a semimajor axis of 2777 \pm 19 km. A multi-year season of mutual events, in which the two near-equal brightness bodies alternate in passing in front of one another as seen from Earth, is in progress right now, and on 2011 Feb. 1 UT, one such event was observed from two different telescopes. The mutual event season offers a rich opportunity to learn much more about this barely-resolvable binary system, potentially including component sizes, colors, shapes, and albedo patterns. The low eccentricity of the orbit and a photometric lightcurve that appears to coincide with the orbital period are consistent with a system that is tidally locked and synchronized, like the Pluto-Charon system. The orbital period and semimajor axis imply a system mass of (10.84 \pm 0.22) \times 10^18 kg, which can be combined with a size estimate based on Spitzer and Herschel thermal infrared observations to infer an average bulk density of 0.72 +0.37 -0.23 g cm^-3, comparable to the very low bulk densities estimated for small transneptunian binaries of other dynamical classes.Comment: In press in Icaru

Consistent Anisotropic Repulsions for Simple Molecules

We extract atom-atom potentials from the effective spherical potentials that suc cessfully model Hugoniot experiments on molecular fluids, e.g., $O_2$ and $N_2$. In the case of $O_2$ the resulting potentials compare very well with the atom-atom potentials used in studies of solid-state propertie s, while for $N_2$ they are considerably softer at short distances. Ground state (T=0K) and room temperatu re calculations performed with the new $N-N$ potential resolve the previous discrepancy between experimental and theoretical results.Comment: RevTeX, 5 figure

Giants On Deformed Backgrounds

We study giant graviton probes in the framework of the three--parameter deformation of the AdS_5 x S^5 background. We examine both the case when the brane expands in the deformed part of the geometry and the case when it blows up into AdS. Performing a detailed analysis of small fluctuations around the giants, the configurations turn out to be stable. Our results hold even for the supersymmetric Lunin-Maldacena deformation.Comment: LaTex, 28 pages, uses JHEP3; v2: minor corrections, references added; v3: final version accepted for publication in JHE

The globalization of naval provisioning: ancient DNA and stable isotope analyses of stored cod from the wreck of the Mary Rose, AD 1545.

A comparison of ancient DNA (single-nucleotide polymorphisms) and carbon and nitrogen stable isotope evidence suggests that stored cod provisions recovered from the wreck of the Tudor warship Mary Rose, which sank in the Solent, southern England, in 1545, had been caught in northern and transatlantic waters such as the northern North Sea and the fishing grounds of Iceland and Newfoundland. This discovery, underpinned by control data from archaeological samples of cod bones from potential source regions, illuminates the role of naval provisioning in the early development of extensive sea fisheries, with their long-term economic and ecological impacts

The hierarchical stability of the seven known large size ratio triple asteroids using the empirical stability parameters

In this study, the hierarchical stability of the seven known large size ratio triple asteroids is investigated. The effect of the solar gravity and primary’s J(2) are considered. The force function is expanded in terms of mass ratios based on the Hill’s approximation and the large size ratio property. The empirical stability parameters are used to examine the hierarchical stability of the triple asteroids. It is found that the all the known large size ratio triple asteroid systems are hierarchically stable. This study provides useful information for future evolutions of the triple asteroids

Electric current circuits in astrophysics

Cosmic magnetic structures have in common that they are anchored in a dynamo, that an external driver converts kinetic energy into internal magnetic energy, that this magnetic energy is transported as Poynting fl ux across the magnetically dominated structure, and that the magnetic energy is released in the form of particle acceleration, heating, bulk motion, MHD waves, and radiation. The investigation of the electric current system is particularly illuminating as to the course of events and the physics involved. We demonstrate this for the radio pulsar wind, the solar flare, and terrestrial magnetic storms

Recent Advances in Understanding Particle Acceleration Processes in Solar Flares

We review basic theoretical concepts in particle acceleration, with particular emphasis on processes likely to occur in regions of magnetic reconnection. Several new developments are discussed, including detailed studies of reconnection in three-dimensional magnetic field configurations (e.g., current sheets, collapsing traps, separatrix regions) and stochastic acceleration in a turbulent environment. Fluid, test-particle, and particle-in-cell approaches are used and results compared. While these studies show considerable promise in accounting for the various observational manifestations of solar flares, they are limited by a number of factors, mostly relating to available computational power. Not the least of these issues is the need to explicitly incorporate the electrodynamic feedback of the accelerated particles themselves on the environment in which they are accelerated. A brief prognosis for future advancement is offered.Comment: This is a chapter in a monograph on the physics of solar flares, inspired by RHESSI observations. The individual articles are to appear in Space Science Reviews (2011